If the painting in its entirety is grey, adding small patches, lines or points of other colors creates an interesting emotion. It is almost as if we can add any kind of color next to grey as long as we can find it in various places strategically throughout the painting.

Note that the mode of the grey painting does not necessarilly have to be such that the grey color should be monolitic. Instead such painting can have many smaller or larger patches of grey which from the distance creates an illusion of homogenous color.

Dark brown in the grey painting can become quite prominent and focused with the addition of the yellow color just as seen in this figure of the tree (top left).